Engineering information straight from the source is rare and almost always anonymous at Eskom, which has strict rules on who can speak in public about its operations.

Business Insider South Africa could not independently verify Technician735's identity or expertise. But we put the information provided to Eskom, and to energy expert and activist Ted Blom.

Eskom did not respond in detail, but Blom told us the information checks out and, if anything, what engineers are seeing is only part of the problem.

The resulting composite picture is a grim one. We know Eskom's current troubles are largely caused by breakdowns, not by the temporary shortage of coal at power stations.

* Does SA export coal? Yes. * Is there a coal shortage in SA? No.* Does Eskom have low coal stockpiles at some power stations? Yes, but the matter is being addressed.* Was the recent loadshedding caused by coal shortage at Eskom stations? No, it was caused by plant breakdowns. https://t.co/BnYJ1RUYDn

But it seems that fixing the underlaying maintenance issues may be worse than previously thought.

Here is what Technician735 claimed, and how those claims stack up.

Half of Eskom’s generating capacity (excluding its two big new stations) is offline and won’t be fully operational for another three years.

Technician735:“From what we have been told 50% of the generating capacity of Eskoms main coal power stations (excluding Kusile and Medupi) are not working and can't be brought fully back online for at least 3 years. So pretty bad, much worse than 2014-2015.”

Blom: “Three years is being optimistic it’s more like 5… Of the 12 power stations in Mpumalanga, 50% of the turbines have stopped because of breakdowns one way to the other. They’re trying to cover up how bad the situation is…[Eskom] don’t want to admit that half of their stations are out of commission.”

Turbines have been badly damaged because Eskom used poor quality coal supplied from mines then owned by the Gupta family.

Technician735:“4 of the 6 turbines at the current power station that i'm working at are seized up. The piping that is supposed to transfer steam to the turbines from the boilers has ruptured due to the wrong grade of coal being used in the past that contains rocks that have exploded...Yep the coal that caused the damage came from the Tegeta mines owned by the Guptas."

Blom: "There are two parts to a generator. The one part is the boiler. The other part next door to it is the turbine. The Brakfontein coal, which was the coal from Tegeta, damaged the high-pressure piping, which acts as the radiator of the boiler. They’re thin pipes, that are used to absorb the heat and turn the water into steam. Those are high pressure systems…You can understand these pipes are very thin, if they are too thick, they won’t absorb the heat. They are vulnerable. If they get a small hairline crack spits out steam like you can’t believe.

Little maintenance was done over the last four years

Technician735:“Yes critical asset maintenance strategies are now in place to ensure intend asset lifetime. One of the main problems we are facing is that little to no maintenance has been done on the plant for at least the past 4 years.”“Under the previous leadership project execution parties were not held accountable to their committed schedules and cost commitments as can be seen with the delays and cost blow out with Medupi and Kusile.”

Blom: “It’s actually longer than that, because in 2010 Eskom took the decision of a ‘lights on at all costs policy’ because of the 2010 FIFA World Cup. That’s when they stopped doing maintenance.

“Come 2014 they brought in Brian Molefe, and he put off preventative maintenance in favour of emergency maintenance. The plan was to plug the holes in the availability gap and eventually catch up to the non-maintenance backlog.

“Over the last four years, Eskom has only performed about half of the maintenance, they haven’t performed the preventative maintenance.”

The Christmas period, with its much lower than usual electricity demand, is not enough time to do critical repairs.

Technician735: [Asked if seized turbines can be fixed over the summer.] “Unfortunately not as the bearings have been badly damage from the lack of oil and maintenance and have to be replaced. Since the bearings can no longer be purchased off the shelf as the [power plant] design is from the late 1950's they have to be custom made and imported which will take a while.”

Blom: "That’s true, some of the parts in the power stations need to be custom made and imported. But that has been true from day one when Eskom built the power stations. Eskom, for whatever reason, has never bought a unit off the shelf. Even Medupi and Kusile are bespoke designs and orders. The moment you do that you immediately create a lack of backup stock. You immediately push up the price of everything. By an investment case Medupi parts would be 10 times the price more expensive than if they had [built it] off the shelf. Whatever part you must replace has to reengineered and replaced."

What is Eskom doing now?

On Thursday Eskom said rolling power cuts may return in January, but there is some relief over the horizon. Eskom confirmed that 930MW from the Koeberg nuclear power station is expected back on line by January and additional capacity from Medupi and Kusile is expected in 2019 at approximately 1,431MW.

In the meantime, President Cyril Ramaphosa appointed an Eskom Sustainability Task Team to advise government on actions to resolve Eskom’s operational, structural and financial challenges.

The team is charged with assessing the operational, structural and financial viability of Eskom, including key assumptions around life of plant, impact and cost of environment commitment, as well as demand assumptions.

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